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How to insert on duplicate update in PostgreSQL?
You can have a WHERE clause on your UPDATE (letting you effectively turn ON CONFLICT UPDATE into ON CONFLICT IGNORE for certain values) The proposed-for-insertion values are available as the row-variable EXCLUDED, which has the same structure as the target table. You can get the original values in the table by using the table name.
How to remove duplicate rows in PostgreSQL with no primary key?
Since you have no primary key you may (ab)use the ctid pseudo column to identify the rows to delete. And probably think about introducing a primary key. The ctid field is a field that exists in every PostgreSQL table and is unique for each record in a table and denotes the location of the tuple.
How to avoid duplicate values for insert in SQL Server?
If it’s a high load environment where another command could insert the duplicate while this command is executing, you can use the WITH (HOLDLOCK) hint. Thanks for contributing an answer to Stack Overflow!
When does an insert succeed in PostgreSQL?
The INSERT will succeed only if row with “id=3” does not already exist. You can combine these two into a single string and run them both with a single SQL statement execute from your application.
How to delete duplicates in PostgreSQL with no unique ID?
Once you delete duplicates you should create a primary key on (user_id, time_id) or create a new unique column for this purpose. Please use any advice on deletions with care, make sure you have a way to “undo it” if needed.
Do you need a unique column in PostgreSQL?
If you don’t want to rely on ctid (personally,I do) ,you can add a unique column (such as a serial) and use that for identity-purposes,
When to use insert on Conflict Statement in PostgreSQL?
The idea is that when you insert a new row into the table, PostgreSQL will update the row if it already exists, otherwise, PostgreSQL inserts the new row. That is why we call the action is upsert (update or insert). To use the upsert feature in PostgreSQL, you use the INSERT ON CONFLICT statement as follows:
When to use upsert or update in PostgreSQL?
The idea is that when you insert a new row into the table, PostgreSQL will update the row if it already exists, otherwise, PostgreSQL inserts the new row. That is why we call the action is upsert (update or insert).
Is there an insert or replace clause in PostgreSQL?
Postgres hasn’t implemented an equivalent to INSERT OR REPLACE. From the ON CONFLICT docs (emphasis mine): It can be either DO NOTHING, or a DO UPDATE clause specifying the exact details of the UPDATE action to be performed in case of a conflict.